1. Field of the Invention
The present invention relates to robot arms and wrist assemblies therefor.
2. Description of the Prior Art
In the prior art there have been various robots designed for use. For example, in Machine Design Magazine, of Aug. 12, 1982, on Page 55, there is an illustration of a robot sold by the Bendix Corporation, Robotics Division of Southfield, Mich. utilizing bevel gear drives for a wrist. The details shown are not extensive, but it does show bevel gears in an arrangement that moves the tool holder shaft through a differential action.
Likewise, U.S. Pat. No. 4,068,536 shows a type of a manipulator hand that provides for three axis movements in a wrist, as well as drives for mounting a robot arm on which the wrist is mounted.
U.S. Pat. No. 4,047,448 shows a robot head that provides for movement of a wrist member about three mutually perpendicular axes, utilizing three separate hydraulic motors for drive and gear trains for accomplishing such drive.
U.S. Pat. No. 4,332,147 shows an adjustable power transmitting device having an input and output shaft which are coupled together by drive gears, and which includes a housing that is rotatably mounted and is adjustable to a plurality of different positions.
A drive is shown in U.S. Pat. No. 3,922,930, requires few drive motors but substantial gear and shafting, and typical manipulator hand operators are shown in U.S. Pat. Nos. 4,188,166; 2,861,701; and 3,817,403.
U.S. Pat. Nos. 4,360,886, and 4,367,532 show devices for providing a program sequence of motions with a robot, and include controller systems for controlling the mechanical construction of the robot.
In addition, another type of manipulator hand is shown in U.S. Pat. No. 3,247,978, but which has its drive motors up near the end of the arm. The hand is driven through various gear drives. This hand, however, does show the use of electromagnetic clutches, which also form part of the present device. The grip operating motor is located down near the hand in this device.
Another type of arm used in manipulators for handling workpieces is shown in U.S. Pat. No. 4,064,656.
An industrial robot utilizing complex gear and shaft drives for obtaining the required motion is further described in U.S. Pat. No. 3,985,238.
None of these, however, have very simple drives for providing a plurality of joint motions in a wrist, shoulder or elbow assembly with gear drives and selectively operable brakes for controlling motions about a plurality of axes for a robot arm and wrist using a minimum number of motors and very simple controls.